The Large Hadron Collider: The world's largest atom smasher

Regarded as the crown jewel of CERN, the Large Hadron Collider (LHC) is an incredible piece of engineering that has allowed physicists to study particle interactions in a manner that cannot be matched by any other particle physics facility in the world.


The LHC is the culmination of 24 years (with 20 of those spent actually constructing the facility) and 10 billion euros. It is capable of accelerating and colliding particles at speeds far greater than any other laboratory, thanks to the way it was built. The collider consists of a 17-mile ring-shaped tunnel that houses several thousand supercooled supermagnets that serve to manipulate the two beams used in experiments.

aAn overlay of
                        the LHC over the countryside it resides under.
The span of the LHC's tunnels, including the location of four detectors.

There are seven detectors in place along the LHC tunnel, each of which serves its own project and team:

  • A Large Ion Collider Experiement (ALICE) - measures and analyzes lead-ion collisions; studies quark-gluon plasma
  • A Toroidal LHC Apparatus (ATLAS) - a general purpose detector that helped to discover and confirm the existence of the Higgs boson
  • The Compact Muon Solenoid (CMS) - a similar function to ATLAS, but uses a solenoid, "a cylindrical coil of superconducting cable that generates a magnetic field of four (teslas)"1
  • The Large Hadron Collider beauty (LHCb) experiment - specializes in the study of the asymmetry observed between matter and its antimatter counterparts by measuring the decay of particles in the twin beams used in the LHC
  • The Large Hadron Collider forward (LHCf) experiment - measures the particles resulting in proton-proton and neutron-proton collsions, with the purpose of estimating and understanding ultra high-energy cosmic rays
  • The TOTal Elastic and diffractive cross section Measurement (TOTEM) experiment - measuring the size of protons at the LHC
  • Monopole and Exotics Detector at the LHC (MoEDAL) - using nuclear track detectors to search for "hypothetical highly ionising particles such as magnetic monopoles"2

aThe
                        Compacy Muon Solenoid (CMS) is one of 7
                        detectors that stands around the LHC
A photograph of the CMS detector.


While the LHC is truly a feat of modern engineering, it has not been without its complications. In September of 2008, the first protons were sent around the accelerator, but the LHC had to be shut down for repairs only 12 days later after an incident resulted in the damaging of 50 supermagents, which prompted a two year shutdown for repairs. In addition, due to its location in the Swiss countryside, the LHC has experiences numerous incidents with wildlife interfering with the facility: in April 2016, a weasel damaged several connections before being electrocuted by a 66,000-volt transformer, causing a week-long closure. In November of the same year, another weasel crossed a substation fence and was subsequently shocked by an 18,000-volt transformer, resulting in another shutdown. In 2009, a piece of a baguette, believed to be a bird's breakfast, was caught in some electric equipment, causing a short that shut down the facility for a period of time.


The LHC has been shut down since December of 2018 for upgrades, and is scheduled to continue smashing atoms in 2021.


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1, 2 - LHC FAQ: The Guide.

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